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Electronic Supplementary Information

Tuning of Metal Enhanced Fluorescence for Sensing Applications

Mainak Ganguly, Chanchal Mondal, Joydeep Chowdhury, Jaya Pal, Anjali Pal, and Tarasankar Pal*

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Figure S1: IR spectrum of CP (cm-1, KBr disk). 1645 (vs, νC=N), 1613, 1583, 1494, 1485, 1465, 1420 (vs or s, νC=C).

500 1000 1500 2000 2500 3000 3500

40

50

60

70

80

90

Tran

smitt

ance

(%)

Wavenumber (cm-1)

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Figure 2: Mass spectra of CP.

(CP + H) (CP + Na)

(CP + K)

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Figure S3: 1H-NMR spectrum of CP in d6-DMSO. δppm: 8.39 (3H, s, OH), 8.23 (2H, s, N=C-H), 6.6-7.4 (12H, m, Ar-H), 2.4-2.8 (12H, m, CH2).

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Figure S4: 13C-NMR of CP in DMSO. δppm: 50.6-57.4 (N-CH2-CH2-N), 79.7 (Ar-CN2), 167.2 (-HC=N), 119 and 133 (C in aromatic ring).

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Figure S5: ESI-mass spectrum of CP capped AgNPs. Peak : 506 (OCP + 2Na + 2H), 612 (OCP + 2Na + Ag), 718 (OCP + 2Na + 2Ag), 824 (OCP + 2Na + 2Ag).

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Figure S6: Excitation spectra of (a) unexposed CP, (b) CP-Ag(I) after one hour exposure and (c) CP-Cu(II) after 14 hours exposure and (d) CP-Au(III) after 11 hours exposure. Condition: [CP] = 1.4 x 10-4 M, [Ag(I)] = 4.2 x 10-4 M, [Cu(II)] = 0.70 x 10-4 M, [Au(III)] = 4.2 x 10-4 M.

200 300 400

0

200

400

600

800

1000

d

c

b

a

Inte

nsity

(a.u

.)

Wavelength (nm)

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Figure S7: Absorption spectra of (a) unexposed CP, (b) CP-Ag(I) after one hour exposure and (c) CP-Cu(III) after 14 hours exposure. Condition: [CP] = 1.4 x 10-4 M, [Ag(I)] = 4.2 x 10-4 M, [Cu(II)] = 0.70 x 10-4 M.

300 400 500

0.0

0.5

1.0

1.5

2.0

2.5

b

ac

Abso

rban

ce (a

.u.)

Wavelength (nm)

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Figure S8: FESEM image of AuNPs obtained as precipitate by adding Ag(I) to the gold hydrosol. Condition: [CP] = 1.4 x 10-4 M, [Au(III)] = 4.2 x 10-4 M, [Ag(I)] = 4.2 x 10-4 M.

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Figure S9: Bar diagram and normalized fluorescence spectra (inset) indicating copper enhanced fluorescence in presence of different interfering metal ions. Conditions: [CP] = 1.4 x 10-5 M, [Cu(II)] = 0.70 x 10-5 M, [other Mn+] = 0.70 x 10-5 M, λex = 290 nm, exposure time = 14 hours.

Ag (I)

+ Cu(

II)

Cu(II)

+ Au

(III)

Cu(II)

+ Ni (

II)

Cu(II)

+ Mg

(II)

Cu (II

)Cu

(II)

+ K

(I)Cu

(II)

+ Ba

(II)

Cu (I

I) +

Mn

(II)

Cu (I

I) +

Cd(II

)Cu

(II)

+ Zn

(II)

Cu (I

I) +

Pb(II

)Cu

(II) +

Co

(II)

Cu(II

) + P

d (II

)Cu

(II) +

Pt (

II)Cu

(II)

+ Hg

(II)Nor

mal

ized

Flu

ores

cenc

e In

tens

ityAg

(I) +

Cu(II)

Cu(II)

+ Au

(III)

Cu(II)

+ Ni (

II)

Cu(II)

+ Mg

(II)

Cu (II

)Cu

(II)

+ K

(I)Cu

(II)

+ Ba

(II)

Cu (I

I) +

Mn

(II)

Cu (I

I) +

Cd(II

)Cu

(II)

+ Zn

(II)

Cu (I

I) +

Pb(II

)Cu

(II) +

Co

(II)

Cu(II

) + P

d (II

)Cu

(II) +

Pt (

II)Cu

(II)

+ Hg

(II)

Ag (I)

+ Cu(

II)

Cu(II)

+ Au

(III)

Cu(II)

+ Ni (

II)

Cu(II)

+ Mg

(II)

Cu (II

)Cu

(II)

+ K

(I)Cu

(II)

+ Ba

(II)

Cu (I

I) +

Mn

(II)

Cu (I

I) +

Cd(II

)Cu

(II)

+ Zn

(II)

Cu (I

I) +

Pb(II

)Cu

(II) +

Co

(II)

Cu(II

) + P

d (II

)Cu

(II) +

Pt (

II)Cu

(II)

+ Hg

(II)

Ag (I)

+ Cu(

II)

Cu(II)

+ Au

(III)

Cu(II)

+ Ni (

II)

Cu(II)

+ Mg

(II)

Cu (II

)Cu

(II)

+ K

(I)Cu

(II)

+ Ba

(II)

Cu (I

I) +

Mn

(II)

Cu (I

I) +

Cd(II

)Cu

(II)

+ Zn

(II)

Cu (I

I) +

Pb(II

)Cu

(II) +

Co

(II)

Cu(II

) + P

d (II

)Cu

(II) +

Pt (

II)Cu

(II)

+ Hg

(II)Nor

mal

ized

Flu

ores

cenc

e In

tens

ity

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Figure S10: 1H NMR of (A) CP and (B) CP-Ag(I) after ~7 hours ageing in alkaline D2O.

A

B

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Figure S11: Raman spectra of solid CP, exposed CP in NaOH and exposed CP-Ag(I) in NaOH.

Condition: [CP] = 1.4 x 10-4 M, [Au(III)] = 4.2 x 10-4 M, Exposure time = one hour.

0 500 1000 1500 2000 2500 3000 3500

0

20000

40000

60000

80000

100000

120000

Silver hydrosolCP in NaOH solid CP

Inte

nsity

(a.u

.)

Raman Shift (cm-1)

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Scheme S1: Mechanism for evolution of coinage metal nanoparticles with the oxidation of CP to its quinone form in aqueous alkaline medium.

N NN NH H

OH HO

HO

CP

OH O-Na+ O

NaOH Ag+

+ Ag(0)

N NN NH H

OH HO

HO

CP

N NN NH H

OH HO

HO

CP

OH O-Na+ O

NaOH Ag+

+ Ag(0)

OHOH O-Na+O-Na+ O

NaOH Ag+

+ Ag(0)NaOH Ag+

+ Ag(0)

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Table S1: Elemental analysis for the compound CP.

Element Calculated (%) Experimental (%) C 70.72 70.80 N 12.22 12.11 H 06.59 06.50

Electronic Supplementary Material (ESI) for Dalton TransactionsThis journal is © The Royal Society of Chemistry 2013